Device for joining two structural parts

ABSTRACT

A device for joining the frames of structural units which are structural units having undercut grooves. The device is provided engages itself in these grooves, and is preferably in the form of a spindle consisting of two parts which rotate with respect to each other on a common threaded shaft or axis. By rotating the defice each of the two parts anchors itself firmly into the undercut grooves in the frames which may be metal sections thus holding the frames together.

Reference is hereby made to companion patent application by HeinrichTeidecken which has issued on May 18, 1976 as U.S. Pat. No. 3,956,863,and is assigned to the assignee of the instant application.

The invention concerns a device for joining two facing structural partswhich exhibit grooves undercut on both sides. Such parts occurespecially in the construction of window or door frames, metal/glasswalls and the like, in particular when a thermal break is desiredbetween the outside and the interior, and for this latter purpose alarge number of suggestions have already been made. These known methodshowever often have disadvantages e.g. complicated, time-consumingassembly, or it is impossible to dismantle the unit without damaging ordestroying the components, making it impossible to re-use the parts.

These disadvantages are avoided by the device of the invention which isbasically a bolt composed of two coaxial parts which can be rotated withrespect to each other, each of the two parts having means which engagesvia a clamping action one of the the shoulders of one of the undercutgrooves.

In other words, the invention is a device for releasably joiningtogether two abutting frames of a structural unit the facing sides ofwhich frames are provided with grooves which are undercut on each sidethereof, in which the device engages. The device comprises a spindle,one end of which carries a releasable means adapted to engage or fitinto the undercut of the groove of a structural frame and the other endof which carries a parallelopipedon of rhomboidal cross-section which isrigidly and transversely attached thereto. The diagonal of theparallelopipedon is sufficiently long so that the parallelopipedon, whencentered in the groove, engages the shoulders of the undercut when thespindle is rotated less than 1/4 of a revolution after insertion in thegroove. The releasable means can be a forked member (as described below)or another parallelopipedon, as described.

The spindle can be cut transversely at its midpoint, in which event theresulting halves are joined by an interior axial bolt.

The bolt is fixed into and projects from one of the halves and isretained in the other half by engagement with axial inner threadstherein. The two halves are thus rotatable with respect to each otherand can be screwed together.

The invention will now be explained in greater detail with the aid ofdrawings showing examples. The FIGS. 1a, 2a, 3a, 4a, 5a and 6a representside views (metal section shown in cross section) of various versionsand FIGS. 1b, 2b, 3b, 4b, 5b and 6b the corresponding plan views, whileFIG. 7 shows an adjustable spanner, likewise in side and plan views, andwhich is suitable for adjusting the device.

The sections to be joined are indicated by 1 and 2, and the device forjoining as a whole by 3. These sections 1, 2 have at least one groove 4running lengthwise on the sides which face each other. These grooves 4are undercut on both sides and have therefore approximatly a T-shape incross section. The flanges 5 which form the limits of the grooves 4have, on their front side, sloping surfaces which run preferably towardsthe interior of the section and counter to each other and serve as stopsfor the connecting device 3. The connecting device 3 has a cross sectionthe shape of a round bolt or spindle. This is made preferably out of aheat insulating material (e.g. plastic). It is made up of thefork-shaped piece 6, rectangular parallelopipedon 7 having a rhomboidalconfiguration in transverse section (hereinafter termed "rhomboidalhead") and a spacer 8 as shown in FIGS. 1a and 5a. These parts arearranged coaxially and are held together by means of screw which islikewise co-axially positioned. The screw 9 requires an internal threadat least in fork-shaped piece 6. It can however also be replaced by abolt fixed in a blind hole (not shown here), whereby the internal threadis omitted. It is also possible instead of an independent screw 9 or anindependent bolt, to provide, as a conjugate part on the hammer headpart 7, a plug which is pressed or injection mould cast on to part 7.However, as is shown in FIG. 2a, the device can be in one piece.

The fork-shaped part 6 exhibits on its end pointing towards section 1two parallel fork-like arms 10 which are provided with snap fitprojections 11 on their outward facing sides. The fork-like arms 10engage in double undercut groove 4 in section 1 so that projections 11anchor themselves behind flanges 5 with a snap fit. The arms 10 arepreferably longer in the direction perpendicular to the long axis of theconnecting device than broad in this plane (see FIG. 1b), so thatfork-like part 6 can not rotate in groove 4. The fork-like part 6 isengaged firmly in groove 4 by pressing or if necessary with a blow. Thescrew 9 which is only then screwed up fully into place forces arms 10outwards and thus ensures that fork-shaped piece 6 can not fall out. Ifscrew 9 is loosened then fork-shaped piece 6 can be moved or dismantled.

The purpose of spacer 8 is to fix the desired distance between sections1 and 2. It can, depending on the requirements e.g. thickness of thefacade panels or panes of glass, be selected longer or shorter (in thedirection of the long axis of the connecting device).

Rhomoboidal head 7 next to spacer 8 has its head 12 at its end facingtowards section 2. In the top view of FIG. 1b, this is trapezium-shapedand only broad enough that it can be introduced into groove 4 of section2. If it is as shown in FIG. 1b then rotated less than 1/4 turn, forexample, by about 75° then it engages in undercut groove 4 and soeffects a connection with section 1 by being locked in place underforce. In order to facilitate easy rotation in groove 4, the edges ofthe head 12 are made to slope in the direction of the long axis andtowards the middle of the device so forming run-in surfaces 13. Theactual head 12 changes to the shape of a cone 15 in the body of headedpart 7. This cone 15, as with that in fork-shaped part 6, facilitateseasy introduction and proper seating of the device in grooves 4 ofsections 1, 2.

Under certain circumstances it can be useful to employ a metal headedscrew instead of a plastic hammer-headed part 7, whereby in the formerthe head and the shaft of the screw form one piece and the shaft of thescrew e.g. is screwed into the fork shaped piece 6 or into a secondheaded part 7. The screw 9 is securely held in the body 16 of the headedpart 7 e.g. by being cast in. In order to rotate this, one uses anadjustable spanner as shown in FIGS. 7a and 7b which can grip twoopposite faces on body 16 of part 7. For this reason body 16 incross-section is usefully multi-sided e.g. with 4, 6 or 8 flat sides asin FIGS. 2a and 2b and the shaft of the adjustable spanner is offsettwice at an angle of 90° (FIG. 7).

It is possible however, instead of an adjustable spanner, to provide onpart 7, as an integral component, lamina rotating means 17 (FIGS. 1a and1b), which extends perpendicular to and transversely from the long axisof the device. The hammer head 12 is rotated by means of this laminauntil it engages in the undercut part of groove 4 of section 1 or 2 asmay be the case.

In a preferred embodiment of the invention, instead of a fork-shaped andpart, two parts 7 are used, only one of which bears a screw 9. A meansfor holding glass in place can also be formed out of one fork-shapedpart 6 or one part 7 alone, together with a screw and a flat rail.

The flat rail can then have the shape of a disc 18 from which a segmenthas been cut away. At the assembly stage this is turned to the e.g.window-pane so that the straight edge 19 faces towards the side on whichthe first sheet of glass is to be put into place. If this sheet is inplace and another sheet is to be mounted on the other side, then thestraight edge 19 is turned 180° towards that side. When both sheets ofglass have been put into place, then the disc is rotated so thatstraight edge 19 lies at a right angle to the long axis of the section.In this way both sheets of glass are held in place by the disc.

In practice a composite section is manufactured in such a way that aplurality of joining pieces of the invention are employed at intervalsbetween two metal sections which are to be joined. The number used isdetermined by the size of the metal section and on the strengthrequirements which have to be satisfied in the construction.

What I claim is:
 1. A device for releasably joining together twoabutting structural unit frames, the facing sides of which are providedwith grooves, undercut on each side thereof, in which the deviceengages, comprisinga spindle, one end of which carries releasable meansadapted to engage the undercut of a groove of said frame, and the otherend of which carries a parallelopipedon of transverse rhomboidalcross-section rigidly and transversely attached thereto, the diagonal ofsaid parallelopipedon being sufficiently long so that saidparallelopipedon, when centered axially in said groove, engages theshoulders of said undercut when said spindle is rotated less than 1/4revolution.
 2. A device according to claim 1, wherein said releasablemeans is a part having two parallel fork-like arms provided withsnap-fit projections on their outward-facing sides adapted to engage theshoulders of said undercut with a snap-fit.
 3. A device according toclaim 1, wherein said spindle is cut transversely at its mid-point andthe resulting halves are joined by an interior axial bolt, said boltbeing fixed into and projecting from one of said halves and beingretained in said other half by axial threads therein, whereby the twohalves are rotatable with respect to each other.
 4. A device, as claimedin claim 1, wherein the spindle carrying said parallelopipedon carriesflat opposite sides, whereby said spindle can be rotated by a thinwrench when said device joins two undercut grooved frames.
 5. A device,as claimed in claim 1, wherein the part of said spindle which carriessaid parallelopipedon carries a lamina projecting transversely from andperpendicular to the long axis of said spindle, whereby said spindle canbe rotated when said device joins two undercut grooved frames.